1. Technical Field
The present invention relates to a semiconductor light emitting element.
2. Background Art
With light emitting diodes (LEDs), semiconductor lasers (LDs), and the like, which are of semiconductor light emitting elements having an n-side semiconductor layer, an active layer, and a p-side semiconductor layer stacked in this order on a substrate, can generate emission of blue and green etc., which have drawn various research and development activities. Generally a method of manufacturing those semiconductor light emitting devices includes disposing a GaN layer on a foreign substrate via an intermediate layer such as a low-temperature buffer layer etc. so as to obtain a flat substrate surface and to decrease occurrence of penetrating pits extending from the foreign substrate, then stacking an n-side semiconductor layer, an active layer, and a p-side semiconductor layer on the GaN layer.
However, in such a method where a GaN layer is grown on a foreign substrate, numerous dislocations in GaN are transferred through the n-side semiconductor layer, the active layer into the p-side semiconductor layer. Particularly, in the case where the active layer contains In, crystal defects increase, resulting in a great drop in non-radiative recombination probability. Meanwhile, various attempts are proposed to obtain a semiconductor light emitting element of high luminosity and high light emitting efficiency, such as varying the thickness of the well layers, or setting the number of unit cycles of a barrier layer and a well layer in the active layer greater at the p-side semiconductor layer side than at the n-side semiconductor layer side (for example, in Japanese Unexamined Patent Application Publication No. 2009-99893A).